Belleville spring-loaded crescent seal

Abstract

PCT No. PCT/US80/00022 Sec. 371 Date Jan. 11, 1980 Sec. 102(e) Date Jan. 11, 1980, PCT Filed Jan. 11, 1980. A sealing structure (10) for use in providing a wide temperature range seal between relatively movable first and second joint members (12,13).The sealing structure includes a dynamic seal element (20) having a lip portion (23) maintained in sealing engagement with the sealing surface (19) of one joint member (13). The seal element is movable with the joint member (13) and is urged to follow the joint member by a spring (22) acting against a surface (31) of the other joint member (12) and having a force-applying portion (32) acting through a load ring force transfer portion (29) to the sealing lip portion (23). The spring further causes the load ring (21) to urge a sealing portion (27) thereof into static sealing engagement with a surface (28) of the joint member (12).

I claim: 
     
       1. In a joint (11) having a first member (12) and a second member (13) variably spaced from said first member, improved sealing structure (20) for providing a seal between said members across the variable space therebetween, said sealing structure comprising: a dynamic seal element (20) having a lip portion (23) sealingly engaging said second joint member (13), and a load portion (24);   a static seal element (21) having a sealing portion (27) sealingly engaging said first joint member (12) and a deflectible force transfer portion (29) engaging said dynamic seal element load portion (24); and   a Belleville spring (22) having a first portion (30) positioned by said first joint member (12), and a second force-applying portion (32) forcibly engaging said force transfer portion (29) of the static seal element (21), a dynamic sealing force being developed between said dynamic seal element lip portion (23) and said second joint member (13) and a static sealing force being developed between said static seal element (21) and said first member (12) as an incident of the spring force transfer through said static seal element deflectible force transfer portion (29).   
     
     
       2. The joint structure of claim 1 wherein said dynamic seal element (20) comprises a seal ring having a crescent cross section defining a load space (26), said static seal element force transfer portion (29) and said spring force-applying portion (32) being disposed in said load space (26). 
     
     
       3. The joint structure of claim 1 wherein said first joint member (12) defines an annular shoulder (31) facing axially toward said second joint member (13), said Belleville spring first portion (30) abutting said shoulder. 
     
     
       4. The joint structure of claim 1 wherein said dynamic seal element (20) comprises a seal ring having a crescent cross section defining a load space (26), said static seal element force transfer portion (20) and said spring force-applying portion (32) being disposed in said load space, said seal ring having an outer leg (25) spaced axially from said lip portion (23) and being free of engagement with said first joint member (12). 
     
     
       5. The joint structure of claim 1 wherein said Belleville spring (22) passes over center in the range of relative movement between said joint members (12,13). 
     
     
       6. The joint structure of claim 1 wherein said static seal element (21) comprises an elastomeric ring. 
     
     
       7. The joint structure of claim 1 wherein said Belleville spring (22) provides a substantially constant spring force on said lip portion (23) of the dynamic seal (20) over the range of relative movement between said joint members (12,13). 
     
     
       8. In a track joint (11) having a link (12), a bushing (13) variably spaced from said link, and thrust means (16) limiting the minimum spacing therebetween, improved sealing structure (10) for providing a seal between said link and bushing across the variable space therebetween over a wide range of temperatures including below-freezing temperatures, said sealing structure comprising: a dynamic seal ring (20) having a crescent cross section defining a lip portion (23) sealingly engaging said bushing (13), and a load portion (24);   a static seal ring (21) having a sealing portion (27) having static sealed engagement with said link (12), and a deflectible force transfer portion (29) engaging said seal ring load portion (24); and   a spring (22) extending between said link (12) and said force transfer portion (29) of the static seal ring (21), a dynamic sealing force being developed between said seal ring lip portion (23) and said bushing (13) and a static sealing force being maintained between said static seal ring (21) and said link (12) as an incident of the compression of said load ring deflectible force transfer portion (29) by said spring (22).   
     
     
       9. The track joint structure of claim 8 wherein said spring (22) comprises a Belleville spring. 
     
     
       10. The track joint structure of claim 8 wherein said spring (22) comprises a Belleville spring arranged to pass over center in the range of relative movement between said link (12) and bushing (13) permitted by said thrust means (16). 
     
     
       11. The track joint structure of claim 8 wherein said thrust means (16) comprises a thrust ring separate from said link (12). 
     
     
       12. The track joint structure of claim 8 wherein said spring (22) has a substantially constant spring constant over said wide range of temperatures. 
     
     
       13. In a joint (11) having a first member (12) and a second member (13) variably spaced from said first member, a bipartite sealing structure (10) for providing a static and dynamic seal between said members across the variable space therebetween, said sealing structure comprising: a dynamic seal element (20) formed of a first material and having a lip portion (23) sealingly engaging said second joint member (13), and a load portion (24);   a static seal element (21) formed of a second material different from said first material and having a sealing portion (27) sealingly engaging said first joint member (12) and a deflectible force transfer portion (29) engaging said dynamic seal element load portion (24); and   spring means (22) forcibly engaging said force transfer portion (29) of the static seal element (21), a dynamic sealing force being developed between said static seal element (21) and said first member (12) as an incident of the spring force transfer through said static seal element deflectible force transfer portion (29).   
     
     
       14. The track joint structure of claim 13 wherein said second material is more rigid than said first material. 
     
     
       15. The track joint structure of claim 13 wherein said first material is an elastomeric material. 
     
     
       16. The track joint structure of claim 13 wherein said first material is an elastomeric material and said static seal is effected by an expansion force in said elastic material acting against one of the joint members as a result of a compression of another portion of the static seal member by said spring means.